code: def hexdigest_sizes_correct(a, digest_size):
      """
      returns True if all hex digest sizes are the expected length in a node:subgraph-hashes
      dictionary. Hex digest string length == 2 * bytes digest length since each pair of hex
      digits encodes 1 byte (https://docs.python.org/3/library/hashlib.html)
      """
      hexdigest_size = digest_size * 2
      list_digest_sizes_correct = lambda l: all(
          len(x) == hexdigest_size for x in l
      )
      return all(
          list_digest_sizes_correct(hashes) for hashes in a.values()
      )
  
imports: import pytest
  import networkx
  from networkx.generators import directed
label_desc: Use image node_id 12 for calling a global function with example usage: hexdigest_sizes_correct(a, digest_size) and returns: all